Question

我在互联网上找到了角度主题的简单例子。我尝试使用示例中的代码，使用subject但我没有获得workTime变量的任何结果。问题出在哪里？

Work.service.ts

import { Subject } from "rxjs/Subject";
import "rxjs/Rx";

@Injectable()
export class WorkService {

  public $workTimeSubject: Subject<number> = new Subject();

  constructor() { }
}

app.component.ts：

export class AppComponent implements OnInit{

  constructor(private _workService: WorkService) { }

  ngOnInit() {
    this._workService.$workTimeSubject.next(40);
    console.log('app init');

    this._workService.setWorkTime(40);
  }
}

Boss.component.ts：

export class BossComponent implements OnInit {

  workTime: number;

  constructor(private _workService: WorkService) { }

  ngOnInit() {
    this._workService.$workTimeSubject.subscribe((value) => {
      this.workTime = value;
      console.log('value', value);
    });
  }
}

boss.component.ts

{{ workTime }}

Answer 1

您的代码中很少有修改，请检查

Work.service.ts：

import { Subject } from "rxjs/Subject";
import "rxjs/Rx";

@Injectable()
export class WorkService {

  private $workTimeSubject: Subject<number> = new Subject();

  updateWorkTime(time: number) {
    this.$workTimeSubject.next(time);
  }

  getWorkTime(): Observable<any> {
    return this.$workTimeSubject.asObservable();
  }
}

app.component.ts：

export class AppComponent implements OnInit{

  constructor(private _workService: WorkService) { }

  ngOnInit() {
    this._workService.updateWorkTime(40);
    console.log('app init');
  }
}

<强> Boss.component.ts：

export class BossComponent implements OnInit {

  workTime: number;
  subscription: Subscription;

  constructor(private _workService: WorkService) {
    this.subscription = this._workService.getWorkTime().subscribe(time => { this.workTime = time; });
  }
}

Answer 2

ORDER BY row_number() OVER (ORDER BY [Project1].[Id] ASC) OFFSET 100 ROWS FETCH NEXT 100 ROWS ONLY在AppComponent有机会订阅之前发出值。如果您希望主题向新订阅者重播上次发出的值，请使用BossComponent。

替换： ReplaySubject

使用： public $workTimeSubject: Subject<number> = new Subject();

Angular 2+和科目

2 个答案: